Method of splicing multifilament yarns by vibratory treatment



May 18, 1965 F. P. STROTHER 3,

METHOD OF SPLICING MULTIFILAMENT YARNS BY VIBRATORY TREATMENT Filed Feb. 28, 1962 2 Sheets-Sheet l 20 5 g 64 3i IJI 72 74 INVENTOR F750 j? STRUT/IE6 yawm, 0M 1W ATTORNEYS United States Patent Ofi ice 3,184,354 Patented May 18, 1965 METHOD OF SPLICING MULTIFILAMENT YARNS I This invention relates to the splicing of yarns, and in particular to the splicing of yarns composed of multiple fibers or filaments of synthetic, thermoplastic materials. The invention involves a method and apparatus for splicing yarns by means of pressure and high frequency vibrations.

In textile operations utilizing continuous yarns, such as in tufting, yarn lengths are commonly spliced one to another by knotting or cementing. Knot splices are bulky and pass through guides, needle eyes and the like only with difficulty, while cemented splices require setting or drying time, and the adhesive used therein is prone to stick to machinery and interfere with free Operation. In ordinary use, cemented splices pick up dirt and appear in the finished product as unsightly defects. These and other conventional splices, accordingly, involve significant disadvantages.

A principal object of the present invention is to provide a method of splicing multifilament yarns, such as carpet yarns, by means of high frequency vibrations, which is easily and quickly accomplished, and results in a small splice of substantially circular cross section, usually smaller than the normal free diameter of the yarn.

Another object of the invention is the provision of a method and apparatus for making novel yarn splices which are strong, stable and secure, uniform and inconspicuous, and capable of passing through guides, eyes, etc., smoothly and without difiiculty. The invention effects splices in which the dye characteristics of the yarn portions joined in the splice are unchanged, whereby the splices remain inconspicuous in the finished product.

A related object of the invention is to provide a simple, portable and durable device for splicing yarns, which requires little effort or skill on the part of the operator, and is almost completely automatic in operation.

Another object is to provide a method of bonding multifilament yarns by the combined effect of solvation agents and ultrasonic energy to provide splices of exceptional strength. Further objects will be in part evident and in part pointed out hereinafter.

The invention and the novel features thereof may best be made clear from the following description and the accompanying drawings, in which:

FIGURE 1 is a sectional view illustrative of the invention, showing two yarns positioned in a die and the tool utilized in splicing;

FIGURE 2 is a sectional view corresponding generally to FIGURE 1, but showing tool and the die in final position, wherein the yarns are spliced;

FIGURE 3 is an elevational view of two yarns spliced in accordance with the invention; 1

FIGURE 4 is an elevational view of an illustrative embodiment of a device incorporating the present invention, with automatic features for closing and opening the energizing circuit thereof;

FIGURE 5 is a sectional view of a portion of the device of FIGURE 4, showing details of the die and its mounting;

"FIGURE 6 is a sectional view taken on the line 66 of FIGURE 4, illustrating constructional details of the die and tool;

FIGURE 7 is a simplified circuit diagram illustrating one energizing circuit for the splicing device;

FIGURE 8 is a simplified circuit diagram illustrating another energizing circuit for the device, and

FIGURE 9 is a diagrammatic illustration of a modified tool and die form, adapted to produce a splice which requires no trimming.

Referring to the drawings, in FIGURE 1 is shown a die 10 of metal or the like provided with a slot 12, the bottom 14 of which is concave and substantially semicylindrical, as shown. The surface 14 or the central portion thereof is preferably in the form of a circular cylinder, but may be otherwise shaped or formed, if desired.

Positioned in slot 14 are yarns 16 and 18, which are composed of multiple fibers or filaments of synthetic, thermoplastic material, such as polyesters, polyamides, polyethylene, polypropylene, polyvinyl chloride, saran and mixtures thereof. The width of the slot 12, it will be noted, is somewhat smaller than the normal free diameter of the yarns, whereby the latter are flattened somewhat in the die slot, as shown. The tool 20 is adapted to enter and fit closely the die slot 12, and the tool face 22 is concave, substantially semi-cylindrical at least in the central portion thereof, and generally complementary to the slot bottom 14.

In accordance with the invention, the tool 20 is advanced and urged into the die slot 12, whereby the yarns I6 and 18 are compressed between the die surface 14 and the tool face 22, and the tool is then vibrated at high frequency, preferably in the ultrasonic range. The compression of the yarns compacts them to the extent that the fiber or filament surfaces thereof touch, andthe ultrasonic energy applied through the tool, in line with the arrow 24 of FIGURE 2, produces heating by interfiber and/or intermolecular friction, causing the fibers or filaments of the yarns to soften, compact and bond to each other, whereby an excellent and permanent bond or splice 25 is effected.

This method is particularly adapted to the bonding of multifilament yarns, and it appears that the application of ultrasonic energy thereto causes interfiber friction which leads to joining of the fiber surfaces. This is particularly advantageous in that the dye characteristics of the yarns so joined are substantially unchanged, and the spliced yarns may be dyed in any common manner without producing any variation in color or shade in the spliced area. It is for this reason desirable to control and limit the quantity of energy applied to the yarns during the splicing operation. As will be evident, excessive application of energy may effect a splice constituting a substantially solid center section or body of material, which would not accept dye in the manner of the adjoining yarns, and would accordingly be conspicuous in the finished product. Moreover, if the splice is virtually solidified, high stress points would exist in the junctions between the individual fibers and the solidified mass, and a materially weaker splice would result.

A completed splice is illustrated in FIGURE 3, and it will be evident that the tag ends 28 and 30, of the yarns 16 and 18 respectively, may be clipped from the completed splice, as along the dotted lines 32. and 34. As shown, the splice Z6 is substantially uniformly compacted and round in cross section, and somewhat smaller than the normal free diameter of the yarns of which it is composed. Being permanently bonded, it is proof against separation, unraveling and the like. Since the splice contains no foreign material such as latex, it offers no impediment to processing of the yarn, and has no more tendency to attract and hold dirt than any other section From the end of the transducer facing lug 44 extends the usual transformer section 48; and the tool 20 is mounted at the outerend thereof. The tool, for reasons and the slot bottom 14, at the longitudinal ends thereof, may be outwardly rounded and flared as at 23 and 15, respectively.

The transistor may be energized to vibrate the tool at frequencies ranging from about 10,000 to 100,000. or

, the range of .050 inch, the width of the die slot and tool presently apparent, is preferably removable, and replaceable, and may be removably mounted in the transformer section in any conventional manner, as by means of screw threads. Inside the lug 44 is mounted the die 10, with its slot 12 facing and aligned with the tool 20.

Means are provided to advance the transducer and tool toward and into the die 10. As shown, a rack 50 is fixedly associated with the transducer 46, and a trigger member 52 is pivotally mounted at 540m the side of the support member 40, the upper end of the trigger member being formed into'a gear segment 56 positionedand adapted to engage the rack 5%). Suitable means, such as the stoplug 58 on the trigger member 52', is provided to limit the rearward movement of the transducer-'46, and a resilient element such as spring 60 may be provided to urge the transducer rearwardly, that'is away from the die 10.

As shown, the spring 60 is fixed to the support memberv and the rack of the transducer, and extends therebetween. Conductors 62 are provided to conduct a high frequency alternating electric current from a source of supply, which may be a high frequency generator, to. the support member 40, and flexible conductors 64 are pro-' vided to'conduct the current from the support member T may be ..040 'inch. The other dimension of the tool, corresponding to the length of the splice effected, may by way of example be .125 inch;

As another feature of the invention, means may be provided to. automate the splicing operation, and to limit the energy and/ or pressure applied to the yarns to prevent excessive solidification thereof. For example, means may be provided to automatically close the transducer. energizing circuit when the force or pressure exerted by the tool 20 against the die 10 through the compressed yarns reaches a predetermined value. As shown in FIGURES 4 and 5,

the support member lug 44. is apertured at 66, and the die 10 is provided with an outwardly extending guide pin 68 adapted to fit and extend through the lug aperture 66. The inner face of lug 44 is provided with a plurality of small leaf springs 70, adapted to engage and normally space the die. from the lug; and a small normally open switch 72 is mounted by means of bracket '74 on the outer face'of lug 44, in such position that when the die 10 is displaced to. the right from theposition shown in FIG- URE 5,.defiecting the springs 70,;the outer end of pin 49 to the transducer 46, it beingunderstood that the con- 7 'd'uctors 62 and 64'are series connected. 7 a

To splice yarns, two respective yarn ends may bepositioned by the operator in the slot 12 of the die 10, preferably in opposed relationship, and thetransducer 46 and V the tool 20 carried thereby are advanceduntil the tool enters'the die slot and compresses the yarns to the extent that. their fibers or filaments are generally in contact,

As will ,be evident, thetool may, remain stationary while the die is displaced theretoward, or, both: elements may be moved with respect to each other.

In the illustrative embodiment, the transducer and tool may be advanced by pivoting the trigger member 52 toward the pistol grip 42, extending the spring 60. When the yarns i are sufficiently compressed between the tool and the. die, 7

the energizing circuit of the transducer may be closed, 7

whereuponthe transducer createsultrasonic waves orvibra'tions which are transmitted by the transformer section to the tool, which in turn applies ultrasonic energyto the compressed yarns, to the end that the fibers or filaments thereof are softened, compacted and securely bonded to each other. Depending on the size and characterof the yarn,- the application of energy may extend for from .less than one second to about ten seconds or more, whereupon the energizing circuit may be opened and. the tool withdrawn. The completed splice may be removed from I This appearsto :be ,due to the tendency of-some fibers to neck down if tensioned during'the application of energy thereof, resulting in weakened yarn sections ad joining the splice. V

.Further to prevent undesired weakening 'of .the yarn ends in such a manner that the transition from the "the-adjoiningyarn sections is gradual. "Eon se,'a's shown inl FIGUREfi, the tool fa ce 22.

. quite uniform.

' 68 will engage and close switch'72. Inthis manner, and

through proper design and adjustment of springsv 72, the transducer energizing circuit may be closed when force or pressure of'a predetermined value is exerted againstthe die by the toolthroughthe compressed yarns, the pressure 'being 'sufficient to deflect springs70 and displace the die to close the switch.s V

The energizing circuit for the transducer may then be as illustrated in FIGURE 7, wherein conductors 76 lead from a source of low frequency alternating current to the high frequency generator 78, whichmay be of conven- 1 tional oscillator or oscillator-amplifier type. Conductors 62 and 64, lead from the high frequency generator to the "transducer 46, and thepressure responsive switch'72 may conveniently be incorporated in one of the conductors 62. It'may be desired, further, to" automatically limit the time of operation of the transducer, and for this purpose a conventional time delay circuit breaker means 80 may be incorporated in the circuit, conveniently in one of the conductors'76. The time delay breaker means may be, for example, a conventional bimetallic thermostatic element, and is preferably adjustable. In 'this manner, the timing of the splicing operation maybe entirely automatic. The operator need only position'the yarns to be spliced in the die slot, and urge the tool thereinto. When the pressure exerted-through the compressed yarns reaches the predetermined value, the energizing circuit will be automatically closed, and then will beautomatically opened after a predetermined; time interval. The resultant splices will be 'In place of a time delay circuit breaker to' open the transducer energizing' circuit, means may be provided to "open the circuit when the entry' rof the tool into thedie slotfreaches a predetermined limit. It will be understood 70 sections adjoining the splice, it has beenfounddesirable V a p to flare or round off the yarn engaging' surfaces at their .thatwhiletheyarns are initially compressed between the tool and die upon the application of high frequency vibrations theretothe yarns are further. compacted, and the extent of such further compaction-may .be'utilized asqa 1 ipracticalllin'iitto terminate the splicing operation. This may be readily and simply accomplished, as illustrated in FTQUREA, by, providing an' exte nsion, 82 on the rack 50, j

whereby it is rigidly associated with the transducer and its tool, and mounting a normally closed switch 34 on the support member 40, as by means of bracket 86, the switch 84 being positioned so that it will be engaged and opened by the rack extension 82 when the tool 20 reaches the preselected position in the die slot 12. In this case, the transducer energizing circuit may be as illustrated in FIGURE 8, wherein conductors '76 lead from a source of low frequency electrical current to the high frequency generator 78, and high frequency alternating current is transmitted from generator 78 through conductors 62 and 64 to the transducer 46. The switches 72 and 84 may be located in either of the conductors 62.

It may be desirable, in order to splice yarns of different sizes and character, to make the die removable and replaceable, so that similar dies having slots of different widths may be readily substituted. This may be accomplished, as illustrated in FIGURE 5, by providing a small pivotal latch 88 in support member 40, the latch being urged outwardly to the position shown by a small leaf spring 90. As will be evident, the latch 88 may be readily pressed inwardly, deflecting spring 90, to clear the die 10, which may then be withdrawn over the latch from the lug aperture 66, and a die of similar dimensions, although with a different die slot, may readily be substituted. When the die is in position, in contact with leaf spring 70, the latch serves to retain the die in place, and prevent further movement away from the support member lug 44. As previously indicated, the tool may be replaceable in the transducer transformer section 48, so that if a die of materially different slot width is substituted, a tool of similar width may also be substituted. As will be evident, means may also be provided for slight adjustment of the switch 84, toward and away from the rack extension 82, so that the limit of entry of the tool into the die slot effective to open the transducer energizing circuit may be varied as desired.

The device may be employed to splice three or more yarns, if desired, and also to splice yarns of synthetic, thermoplastic material to yarns of other material. A nylon yarn may be spliced to a cotton yarn, for example, although in such case it is usually necessary to apply greater pressure, and for a greater length of time, to attain an effective splice. Similarly, non-thermoplastic yarns may be spliced to each other, with the aid of a short piece of thermoplastic yarn. In this manner, a short piece of nylon yarn may be sandwiched between two cotton yarns, and the assembly spliced in the manner described.

It is known to join fibers and yarns through the action of solvation agents, by which is meant materials effective to soften and/or swell the surfaces of fibers. The solvation action of these materials is commonly assisted by means of pressure and/or heat. For example, zinc chloride, Zinc bromide and ferric chloride are effective solvation agents for nylon fibers. Calcium and magnesium thiocyanates are effective solvation agents for polyester fibers. It has been found that exceptionally strong splices can be effected in accordance with the present invention, by treating the yarn sections to be spliced with an appropriate solvation agent, immediately prior to the application of ultrasonic energy thereto.

In accordance with another aspect of the invention, the tool or die form may be modified to automatically shear the yarn ends in the course of the splicing operation, and thereby produce a splice requiring no subsequent trimming. As diagrammatically illustrated in FIGURE 9, the

die 91 may be provided with an outwardly extending lug 92, offset laterally from the die working face 94. The associated tool 96 will be coextensive with the working face 94- of the die, as shown. For splicing in accordance with this tool and die form, the yarns 98 and 100 are arranged in parallel relationship with ends extending in the same direction. In such case, if ultrasonic energy is applied to the tool at the initiation of the advance of the tool and die toward each other, the yarns will be sheared along the dotted line 102, between the lug 92 and the adjacent end of tool 96, as the elements approach splicing position, and the resultant splice will be free of tag ends. This manner of splicing is particularly advantageous when the necessity for maintaining the spliced yarn in linear arrangement is not critical. In all other respects, the splicing in accordance with this practice may be effected in accordance with the. procedures and embodiments described above.

It will thus be seen that there has been provided by this invention apparatus and methods in which the various objects hereinbefore set forth, together with many practical advantages, are successfully achieved. As various possible embodiments may be made of the several features of the above invention, all without departing from the scope thereof, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative, and not in a limiting sense.

I claim:

1. Method of splicing multifilament yarns comprising the steps of compressing the yarns between a tool and a die, and simultaneously vibrating said tool at high frequency to soften, compact and bond the fibers of said yarns together.

2. Method of splicing multifilament yarns of thermoplastic material comprising the steps of compressing the yarns between a tool and a die, vibrating the tool at high frequency to soften, compact and bind the fibers of said yarns together, and terminating the vibration of said tool at the end of a predetermined time period to limit the extent of compaction of said yarns.

3. Method of splicing multifilarnent yarns of thermoplastic material comprising the steps of compressing the yarns between a tool and a die, vibrating the tool at high frequency to soften, compact and bind the fibers of said yarns together, and terminating the vibration of said tool when the tool and die reach a predetermined approach point with respect to each other, to limit the extent of compaction of said yarns.

4. Method of splicing multifilament yarns of thermoplastic material comprising the steps of applying a solvation agent to said yarns, compressing the yarns between a tool and a die, and vibrating the tool at high frequency to soften, compact and bind the fibers of said yarns together.

References Cited by the Examiner UNITED STATES PATENTS 2,514,197 7/50 Groten et al. 156--158 2,633,894 4/53 Carwile 15673 2,853,118 9/58 Schnitzius 156-423 2,954,815 10/60 Kuts 15673 3,022,814 2/62 Bodine 15673 3,078,912 2/63 Hitzelberger 156-582 EARL M. BERGERT, Primary Examiner. 

1. METHOD OF SPLICING MULTIFILAMENT YARNS COMPRISING THE STEPS OF COMPRESSING THE YARNS BETWEEN A TOOL AND A 